Lesson 10 Flashcards
(26 cards)
proportion of each species
relative to total number of
individuals of all species
living in community
relative abundance
plots rank abundance (x-axis)
against corresponding relative
abundance (y-axis)
rank abundance diagram
components of species diversity
richness and evenness
number of species in the
community
- longer the curve, greater the
richness in community
species richness
how equally individuals are distributed among the species - more gradual the slope, greater the evenness in communit
species evenness
refers to three closely related
indices that consider both species
number and relative abundance
simpsons diversity index
three indices of simpsons
Simpson’s index D
- Simpson’s index of diversity 1 − D
- Simpson’s reciprocal index 1 / D
probability that two randomly selected individuals from community will belong to same species, reflects DOMINANCE
simpsons index
probability that two randomly
selected individuals from
community will belong to
different species
simpsons index of dveersity
maximum value is the
number of species in the
community, species richness
(S)
simpsons reciprocal index
widely used index of diversity
shannon index
representation of feeding relationships within a community ● a descriptive diagram representing flow of energy from prey (consumed) to predator (consumer)
food chain
direction of arrow in the food chain
prey to
predator grass → grasshopper →
sparrow → hawk
feeding groups are called
trophic levels
usually autotrophs
basal species
herbivores (H) or carnivores
intermediate species
Top predators
not preyed upon themelves
Food web could be divided into five
compartments based on
- differences in body size
- range of prey sizes selected
- use of shore versus off-shore habitats
- associated predators
- abundance of populations is
controlled by productivity and
abundance of populations in trophic
level below them
bottom up control
predator populations control the
abundance of prey species
top down control
removal of top predator results in increase
in intermediate species on which it preys
food web trophic cascade
describes total competitive effects of
several interspecific competitors
diffuse competition
Spatial change in community
structure
zonation
Temporal change in
community structure at a given location
succession